|MadSci Network: Chemistry|
We have been doing air pressure demos in class. One that we did was to fill a jar to the rim with water, cover it with a piece of cardboard, and turn it upside down, observing that the water did not spill when I took off my hand. However when the jar was half full, the water spilled out. I thought this might have more to do with the suction of the cardboard on the cup, but my teacher said it was because of air pressure. I cannot understand how air pressure "works" in all directions. Can you explain this to me?
Re: how does air exert pressure in all directions?
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